MTR vibration on the freeway? Or DS vibration? (1 Viewer)

[DiscoveredLC]

I have a vibration (you can hear it through the truck) on the freeway, and I cant tell if its the drivelines or the new MTR's.

I had bayshore in sparks rebuild my front DS and they said I should put it back IN phase (stock 80's have the DS out of phase factory) now that the truck is lifted. The vibration still seems to be the same at freeway speeds. Since the pinion and tcase flanges arent even close to being parallel, I figured I needed a CV joint style DS, but the guys at bayshore said no. Im going to check out the rear driveline tomorrow to see how those joints feel.

I dont seem to remember having any vibration issues when I had the BFG all terrains on the truck, and the lift was exactly the same then. So thats why im wondering if its the new more aggressive MTR's

Dan, do you coast down the freeway smooth as butter in your 100, or do you feel some vibration due to the MTR's?

 

[spressomon]

Funny you should ask. Apart of a recent 4,200 mile trip to the midwest and back...and then to DV I swapped my extra wheel set with the Toyo OC ATs onto the 100. I could feel a little vibe around 70mph +/- but on the way back from the big trip #1, with the KK in tow BTW, around Hot Springs we felt a much more significant vibe and associated drone. With all the miles I've put on with the MT/Rs installed I couldn't specifically feel or hear the drivetrain.

I pulled the rear drive shaft and ran around in FWD and the vibe was not present. Although at certain speed ranges I could now feel a little vibe in my front DS...but not enough to concern me.

So then I swapped my old rear DS and it was plain ass terrible (vibes from 40+).

So in answer to your question: I don't think you can diagnose drive-line vibes with most MT tread tires...the GY Kevlar MT/R being no exception.

At rest height my pinion flange is 3.2 degrees with 2 degrees being ideal per specs. But I've messed with drivelines enough to know with: A relatively short wheel base rig #1, Land Cruiser #2 (80's and 100's are especially prone to chassis vibes...this even caused the Toyota engineers to become exacerbated to the point of adding an iron damping puck on the 100 frame!), lift #3 and lower gears/higher driveline RPM #4 pinion to t-case flange needs to be set by experimentation on problematic rigs like mine.

So I'm going to fab another set of adjustable rear upper control arms with 80-bushings to play around with pinion angle again...with the AT tires on board.

 

[DiscoveredLC]

I dont seem to ever remember a driveline vibe on the freeway when I had my BFG AT's on... I drove the truck around 70 75 mph many times over and it seemed to drive just fine. Thats why I find it hard to believe that its all of a sudden developed a driveline issue. The rear shaft is still at factory u joints, so I'm going to replace those anyways. I installed a set of MAF UCA's last week. The pinion and tcase are dead on mirror image of eachother.

The thing that concerns me is the front. The whole debate about whether or not the front should be IN phase or OUT of phase has me scratching my head. The pinion and t case angles just seem weird to me... I figured a CV shaft up front would work best since the pinion and DS are only about 3-4* off from each other. Bayshore said i'll be better off running a standard 2 joint shaft in phase.

Iknow the truck will never drive as smooth as I want it to, but I just want to be sure there arent any issues that would cause damage to the diff or drivelines after a long period of time.

 

[DiscoveredLC]

One thing i have noticed with these tires though, they do not like the cold. Maybe its from the Kevlar sidewalls, but I can feel what seems to be a "flat" spot after a cold night in the driveway. Like the tire is so stiff when I start driving that I can feel the flat area from being parked all night in the cold.

 

[spressomon]

Those upper arms, actually not the arms but the ends, will add just a little buzz to the suspension compared to OEM rubber.

 

[spressomon]

Well...too bad you're on 6 stud and I'm on 5...lest I let you borrow my wheels and AT tires. You just can't diagnose driveline vibes/issues with MT tread.

 

[locrwln1]

As Dan has said, 80's and 100's are very sensitive to driveline angles and vibes. Both Dan and I have talked to Slee and he said that he can build 4 rigs exactly the same and one will have vibes and the others won't or it can be vice versa. And yes you will go nuts trying to fully eliminate them.

I got my 80 down to the slightest vibe on a downhill decel. That was the best I could get it.

Before you replace the u-joints in the rear shaft, do yourself a favor and just order a replacement shaft (new and complete) from Onur. By the time you buy and wrestle new u-joints in and have it checked for balance, you can buy a new one and just bolt it in. The slip yokes wear out on driveshafts and you can't fix that. All you can do is replace it.

As far as the front shaft. Find a Tacoma ex-cab rear CV shaft and have Bayshore cut it down. They bolt right in (after shortening of course).

That was the best combo I came up with. Good luck with the battle.

Jack

 

[RAYJON]

take a look at this

https://forum.ih8mud.com/80-series-tech/199148-double-cardan-drive-shaft-solutions.html

 

[DiscoveredLC]

Well i now have a DC front shaft in that I had built from a tundra by Bayshore.

There's still a noticeable drone (it isnt constant, it goes up and down randomly) at freeway speeds. The vibration isnt constant either....

Wouldnt a driveshaft vibe be constant? I dont know if its the tires, but I highly doubt the tires cause a vibration like this. I think it has to be the rear shaft.

Dan, do you have your MTR's on your 100? Maybe you can drive my truck and see how the ride feels compared to yours...

 

[spressomon]

Matt,
Right now I have the Toyo AT wheels on my 100. I can tell you the MTR's have a vibe and a drone.

FWIW per Onur, during one of our conversations about same on our trip last month, said they (American Toyota) are stocking complete rear drive shaft assemblies for 80's and 100's because they discovered when the u-joints get to the point of needing to be replaced, due to wear, the splines apart of the yoke are worn and contribute to driveline vibe, clunking (100's are notorious for clunking during start/take-off from stop...think 80's too)...

I'm going to convert my rear UCA to adjustable's and play with the pinion angle again.

 

[rusty_tlc]

Matt,
Right now I have the Toyo AT wheels on my 100. I can tell you the MTR's have a vibe and a drone.

FWIW per Onur, during one of our conversations about same on our trip last month, said they (American Toyota) are stocking complete rear drive shaft assemblies for 80's and 100's because they discovered when the u-joints get to the point of needing to be replaced, due to wear, the splines apart of the yoke are worn and contribute to driveline vibe, clunking (100's are notorious for clunking during start/take-off from stop...think 80's too)...

I'm going to convert my rear UCA to adjustable's and play with the pinion angle again.

I can verify this, we just replaced the rear DL U-joints and still have a little vibration. Not bad, in fact barely noticeable since we swapped the Toyo MTR's to Michelin LTX A/t2's.